Free migration or open immigration is the position that people should be able to migrate to whatever country they choose with few restrictions.
From a human-rights perspective, free migration may be seen to complement Article 13 of the Universal Declaration on Human Rights:
Everyone has the right to freedom of movement and residence within the borders of each State.
Everyone has the right to leave any country, including his own, and to return to his country.
War-related chaos can lead to the breakdown of borders and allow for de facto free immigration. The natural attempts to flee strife, or escape a conquering enemy, can quickly lead to millions of refugees. Even where border controls are in place they can be overwhelmed by the sheer numbers of people. Once settled into refugee camps, these reluctant immigrants may take decades to be either repatriated back or naturalized into their new country. This has been the situation with the Palestinians in Jordan.
During the Cold War, a migration paradox arose in which some of the communist states forbade emigration, while the "Free World" would freely accept the defectors. This policy persists for Cubans and the Hmong, who are both allowed particular forms of free immigration to the United States based on their automatic refugee status.
The Citizens’ Rights Directive (Europe)
The Eurasian Economic Union (EAEU)
The Economic Community of West African States (ECOWAS)
The Treaties of Friendship between India and Bhutan and between India and Nepal
The Trans-Tasman Travel Arrangement between New Zealand and Australia
The Compact of Free Association between the United States and the Marshall Islands, Micronesia and Palau
The CARICOM Single Market and Economy (CSME in the Caribbean) (with restrictions)
Citizenship of the Mercosur (South America)
The Common Travel Area "between the United Kingdom, the Crown Dependencies (Bailiwick of Jersey, Bailiwick of Guernsey and the Isle of Man) and Ireland"
The Central America-4 Border Control Agreement between El Salvador, Guatemala, Honduras, and Nicaragua
Visa policy of Svalbard
All people, regardless of citizenship are allowed to live and work in Svalbard without a visa or residence permit, as long as they demonstrate they are able to support themselves.